In the ink jet printing process, suitable support of the print media during printing aids in achieving acceptable print quality. Such support can include holding sheet media flat against a media supporting member, or platen, to ensure the ink maintains suitable properties during printing.
In addition, it may be desirable that a media sheet be heated uniformly as it rests on the printer platen, in order to achieve acceptable print quality. A technique, in pursuit of this goal, is to heat the platen to a suitable temperature. This is sometimes accomplished by the use of heating strips disposed against the sidewalls of the platen. While this technique results in effective heating of areas of the platen surface, it can fail in some instances to provide uniform heating over the platen surface. The result can be a diminution in print quality because of temperature gradients across the platen producing unevenly heated media sheets.
Where the term xe2x80x9cimage transfer systemxe2x80x9d is used in this description, the term is meant to encompass a variety of such devices, including printers, facsimile devices and scanners. For convenience, the term xe2x80x9cprinterxe2x80x9d will be used in this written description but it should be understood that the description is intended broadly, to cover such other devices.
Another factor adversely affecting print quality may be a failure to draw the media sheet against the platen in a uniform manner. This is especially the case at the ends of the platen where air passes under media edges, thereby tending to raise the media away from the platen
Airflow at the media edges allows cool air to pass under the edges as the air flows generally toward the center of the media for evacuation. This airflow can produce an uneven temperature distribution across the media as portions of the media are raised away from the heated platen. Again, the result adversely impacts print quality. In addition, if air flows freely under media edges, a potential develops whereby the edges lifting from the platen surface may contact printheads thereby causing print defects, paper jams and, in some cases, damage to the printer.
An image transfer system includes a member for supporting print media, the member including a pair of sidewalls depending therefrom, a pair of end caps, wherein one end cap is connected to the sidewalls at an end thereof and the other end cap is connected to the opposite end of the sidewalls, and a heating element disposed against the underside of the member and in contact with each of sidewalls and end caps.